WO2020134201A1

WO2020134201A1 - Method for manufacturing quantum dot light emitting diode

Info

Publication number: WO2020134201A1
Application number: PCT/CN2019/106131
Authority: WO
Inventors: 张节; 向超宇
Original assignee: Tcl科技集团股份有限公司
Priority date: 2018-12-29
Filing date: 2019-09-17
Publication date: 2020-07-02
Also published as: CN111384308B; CN111384308A; US12209215B2; US20220089948A1

Abstract

A method for manufacturing a quantum dot light emitting diode, comprising the following steps of: providing a substrate, the upper surface of the substrate being provided with a quantum dot light emitting layer (S10); and immersing the substrate in a solvent system then for ultrasonic treatment, the solvent system comprising a main solvent and a doping solvent dissolved in the main solvent, the polarity of the doping solvent being less than the polarity of the main solvent, and the main solvent being an organic solvent that does not dissolve quantum dots (S20).

Description

Method for preparing quantum dot light-emitting diode

[0001] This application claims the priority of the Chinese patent application filed on December 29, 2018 in the Chinese Patent Office, with the application number 201811639647.3 and the application name "Method of Manufacturing Quantum Dot Light Emitting Diodes", the entire contents of which are cited by reference Incorporated in this application.

Technical field

[0002] The present application relates to the field of display technology, and in particular to a method for manufacturing a quantum dot light emitting diode.

Background technique

[0003] quantum dot

dots), also known as semiconductor nanocrystals, whose three-dimensional dimensions are in the nanometer range (l-100nm), is a kind of nanoparticle theory between bulk materials and molecules. Quantum dots have excellent optical properties such as high quantum yield, large molar extinction coefficient, good light stability, narrow half-width, broad excitation spectrum and controllable emission spectrum, and are very suitable for use as light-emitting materials for light-emitting devices. In recent years, quantum dot fluorescent materials have been widely used in the field of flat panel displays due to their advantages of high light color purity, adjustable luminous color, and long service life. They have become a promising next-generation display and solid-state lighting source. Quantum dot light emitting diodes (Quantum Dot Light Emitting Diodes QLED) are light-emitting devices based on quantum dot materials as luminescent materials. Due to their advantages of tunable wavelength, narrow emission spectrum, high stability, high electroluminescence quantum yield, etc. A strong competitor of a generation of display technology.

[0004] However, the current manufacturing method of the quantum dot light emitting diode still needs to be improved.

Summary of the invention

technical problem

[0005] The inventor found that during the preparation process of the QLED device, since the quantum dot itself inevitably contains impurities, the resulting quantum dot light emitting layer will introduce impurities, which affects the luminous efficiency and service life of the quantum dot light emitting diode. The solution processing method is a common method for preparing QLED devices. In particular, with the development of technology, it has become conventional to prepare quantum dot light-emitting layers using inkjet printing technology. However, when the quantum dot light-emitting layer is prepared by a solution processing method such as inkjet printing, part of the solvent of the quantum dot ink remains during film formation, especially during inkjet printing, in order to slow down the printing drying speed, a high boiling point is added to the quantum dot ink Solvent, high boiling Point solvent residues also contribute to the luminous efficiency and service life of quantum dot LEDs.

[0006] One of the purposes of the embodiments of the present application is to provide a method for preparing a quantum dot light-emitting diode, which aims to solve the problem And/or impurities formed by residual solvent), a problem that affects the luminous efficiency and service life of quantum dot light-emitting diodes.

Solution to the problem

Technical solution

[0007] To solve the above technical problems, the technical solutions adopted in the embodiments of the present application are:

[0008] In a first aspect, a method for manufacturing a quantum dot light emitting diode is provided, including the following steps:

[0009] providing a substrate on which a quantum dot light emitting layer is provided;

[0010] The substrate is immersed in a solvent system for ultrasonic treatment, the solvent system includes a host solvent and a doping solvent dissolved in the host solvent, the polarity of the doping solvent is less than that of the host solvent And the host solvent is an organic solvent that does not dissolve quantum dots.

[0011] In one embodiment, the host solvent is selected from alcohols with a linear number of carbon atoms less than 20, esters with a linear number of carbon atoms less than 20, and carbon numbers with a linear number of less than 20 One or a combination of two or more ketones.

[0012] In one embodiment, the alcohols having less than 20 carbon atoms in the linear chain are selected from 1-propanol, 1-butanol, 1-pentanol, 2-pentanol, 1,5-pentanol One or more of diol and 2,3-butanediol;

[0013] The esters having less than 20 carbon atoms in the linear chain are selected from ethyl acetate, ethyl propionate, ethyl methacrylate, and ethyl benzoate;

[0014] The ketones having less than 20 carbon atoms in the linear chain are selected from acetone, methyl ethyl ketone, 3-pentanone, 2-methyl 4-octanone.

[0015] The alcohol derivative having less than 10 carbon atoms in the linear chain is selected from one or more of methoxyethanol, ethoxyethanol, ethyl mandelic acid, and the like.

[0016] In one embodiment, the doping solvent is selected from unsaturated fatty acids with less than 10 carbon atoms in the linear chain, alcohol derivatives with less than 10 carbon atoms in the linear chain, and carbon in the linear chain One or a combination of two or more of saturated acids with less than 10 atoms, acid derivatives with less than 15 carbon atoms in the linear chain and halogenated hydrocarbons with less than 20 carbon atoms in the linear chain. [0017] In one embodiment, the unsaturated fatty acid having less than 10 carbon atoms is selected from one or more of acrylic acid, crotonic acid, methacrylic acid, and 3-pentenoic acid;

[0018] The alcohol derivative having a carbon number of less than 10 in the linear chain is selected from one of methoxyethanol, ethoxyethanol, ethyl 2-hydroxy-2-phenylacetate and acetol Multiple

[0019] The saturated acids having less than 10 carbon atoms in the linear chain are selected from one or more of acetic acid, propionic acid, butyric acid and valeric acid;

[0020] The acid derivatives having less than 15 carbon atoms in the linear chain are selected from one or more of perfluorooctanoic acid, perfluorodecylphosphonic acid, perchlorodecylcarboxylic acid and perfluorododecanoic acid ;

[0021] The halogenated hydrocarbons having less than 20 carbon atoms in the linear chain are selected from fluoropropane, 1-chlorobutane, 1-chlorohexane and 3

-One or more of fluorohexane.

[0022] In one embodiment, based on the total weight of the solvent system is 100%, the weight percentage of the doping solvent is 0.001-0.5%.

[0023] In the step of immersing the substrate in a solvent system for ultrasonic treatment, the frequency of the ultrasonic treatment is 20 kHz-10 ⁹ kHz.

[0024] In one embodiment, in the step of immersing the substrate in a solvent system for ultrasonic treatment, the frequency of the ultrasonic treatment is 20 kHz-100 kHz.

[0025] In one embodiment, in the step of immersing the quantum dot light emitting layer in a solvent system for ultrasonic treatment, the power density of the ultrasonic treatment is 0.3-200 w/cm ² .

[0026] In one embodiment, in the step of immersing the quantum dot light-emitting layer in a solvent system for ultrasonic treatment, the power density of the ultrasonic treatment is 5-100 w/cm ² .

[0027] In one embodiment, the step of immersing the quantum dot light-emitting layer in a solvent system for ultrasonic treatment, the ultrasonic treatment time is 20 minutes-48 hours.

[0028] In one embodiment, in the step of immersing the quantum dot light emitting layer in a solvent system for ultrasonic treatment, the ultrasonic treatment time is 1 hour -10 hours.

[0029] In one embodiment, the substrate is a substrate provided with a bottom electrode.

[0030] In one embodiment, the bottom electrode is an anode, and before preparing the quantum dot light emitting layer, a step of preparing a hole functional layer on the anode surface of the substrate is further included; the hole functional layer includes holes At least one layer of the injection layer, the hole transport layer, and the electron blocking layer. [0031] In one embodiment, the bottom electrode is an anode, and before preparing the cathode, the method further includes a step of preparing an electronic functional layer on a side of the quantum dot light-emitting layer facing away from the anode; the electronic functional layer includes At least one of the electron injection layer, the electron transport layer, and the hole blocking layer.

[0032] The beneficial effects of the preparation method of the quantum dot light emitting diode provided by the embodiments of the present application are as follows: After the quantum dot light emitting layer is prepared, the quantum dot light emitting layer is immersed in a solvent system for ultrasonic treatment. Wherein, the solvent system includes a host solvent and a doping solvent dissolved in the host solvent, the polarity of the doping solvent is less than the polarity of the host solvent, and the host solvent is insoluble in quantum dots Organic solvents. Through ultrasonic treatment, the solvent system penetrates into the quantum dot light-emitting layer to dissolve impurities in the quantum dot light-emitting layer (impurities introduced by the quantum dot itself and/or impurities formed by residual solvent), thereby removing residual impurities to the quantum dot light-emitting diode The influence of luminous efficiency and service life ultimately improves the luminous efficiency and service life of quantum dot light-emitting diodes.

Beneficial effects of invention

Brief description of the drawings

BRIEF DESCRIPTION

[0033] In order to more clearly explain the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings used in the embodiments or exemplary technical descriptions. Obviously, the drawings in the following description are only For some embodiments of the present application, for those of ordinary skill in the art, without paying any creative labor, other drawings may be obtained based on these drawings.

[0034] FIG. 1 is a schematic flowchart of a method for manufacturing a quantum dot light emitting diode according to an embodiment of the present application.

Invention Example

Embodiments of the invention

[0035] In order to make the purpose, technical solutions and advantages of the present application more clear, the following describes the present application in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application, and are not intended to limit this application.

[0036] It should be noted that the terms “first” and “second” are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application , "Multiple" means two or more, unless otherwise specifically limited.

[0037] In order to explain the technical solutions described in the present application, the following detailed description will be made in conjunction with specific drawings and embodiments.

[0038] As shown in FIG. 1, some embodiments of the present application provide a method for manufacturing a quantum dot light emitting diode, including the following steps:

[0039] S 10 provides a substrate on which a quantum dot light emitting layer is provided;

[0040] S20 immersing the substrate in a solvent system for ultrasonic treatment, the solvent system includes a host solvent and a doping solvent dissolved in the host solvent, the doping solvent has a polarity less than that of the host solvent Polarity, and the host solvent is an organic solvent that does not dissolve quantum dots.

[0041] The preparation method of the quantum dot light emitting diode provided in the embodiments of the present application, after the quantum dot light emitting layer is prepared, the quantum dot light emitting layer is immersed in a solvent system for ultrasonic treatment. Wherein, the solvent system includes a host solvent and a doping solvent dissolved in the host solvent, the polarity of the doping solvent is less than the polarity of the host solvent, and the host solvent is insoluble in quantum dots Organic solvents. Through ultrasonic treatment, the solvent system penetrates into the quantum dot light-emitting layer to dissolve impurities in the quantum dot light-emitting layer (impurities introduced by the quantum dot itself and/or impurities formed by residual solvent), thereby removing residual impurities to the quantum dot light-emitting diode The influence of luminous efficiency and service life ultimately improves the luminous efficiency and service life of quantum dot light-emitting diodes.

[0042] Specifically, the quantum dot light emitting diode is divided into a positive structure and an inverse structure. The positive structure includes an anode, a cathode, and a quantum dot light emitting layer disposed between the anode and the cathode. The anode of the positive structure is disposed on the substrate, and hole transport may be provided between the anode and the quantum dot light emitting layer. The hole functional layer such as a layer, a hole injection layer, and an electron blocking layer may be provided with an electron functional layer such as an electron transport layer, an electron injection layer, and a hole blocking layer between the cathode and the quantum dot light emitting layer. The inversion structure includes an anode, a cathode, and a quantum dot light emitting layer disposed between the anode and the cathode. The cathode of the inversion structure is disposed on the substrate, and hole transport can also be provided between the anode and the quantum dot light emitting layer. The hole functional layer such as a layer, a hole injection layer, and an electron blocking layer may be provided with an electron functional layer such as an electron transport layer, an electron injection layer, and a hole blocking layer between the cathode and the quantum dot light emitting layer.

[0043] In the above step S10, for a positive device, the bottom electrode provided on the substrate is an anode. In one embodiment of the present application, the substrate may be provided with a bottom electrode on the substrate and a A quantum dot light emitting layer on the surface of the bottom electrode; in yet another embodiment of the present application, the substrate may include a substrate and a layer A bottom electrode stacked on the surface of the substrate, a hole transport layer stacked on the surface of the substrate, and a quantum dot light emitting layer disposed on the surface of the hole transport layer; in yet another embodiment of the present application, the substrate may It includes a substrate, a bottom electrode stacked on the surface of the substrate, a hole injection layer stacked on the surface of the substrate, a hole transport layer stacked on the surface of the hole injection layer, and quantum dots provided on the surface of the hole transport layer Light emitting layer; in still another embodiment of the present application, the substrate may include a substrate, a bottom electrode stacked on the surface of the substrate, a hole injection layer stacked on the surface of the substrate, and a hole injection stacked on the surface A hole transport layer on the surface of the layer, an electron blocking layer stacked on the surface of the hole transport layer, and a quantum dot light emitting layer provided on the surface of the electron blocking layer.

[0044] For an inversion device, the bottom electrode provided on the substrate is a cathode. In an embodiment of the present application, the substrate may be provided with a bottom electrode on the substrate; in another embodiment of the present application In an embodiment, the substrate may include a substrate, a bottom electrode stacked on the surface of the substrate, an electron transport layer stacked on the surface of the substrate, and a quantum dot light emitting layer disposed on the surface of the electron transport layer; In one embodiment, the substrate may include a substrate, a bottom electrode stacked on the surface of the substrate, an electron injection layer stacked on the surface of the substrate, a hole transport layer stacked on the surface of the electron injection layer, and A quantum dot light emitting layer on the surface of the electron transport layer; in still another embodiment of the present application, the substrate may include a substrate, a bottom electrode stacked on the surface of the substrate, an electron injection layer stacked on the surface of the substrate, An electron transport layer provided on the surface of the electron injection layer, a hole blocking layer provided on the surface of the electron transport layer, and a quantum dot light emitting layer provided on the hole blocking surface are stacked.

[0045] Specifically, in the above step S10, a substrate provided with a bottom electrode is provided, that is, a bottom electrode is provided on the substrate. The selection of the substrate is not strictly limited, and a rigid substrate such as a glass substrate may be used; a flexible substrate such as a polyimide substrate or a polynorbornene substrate may also be used, but it is not limited thereto. The bottom electrode is an electrode opposite to the top electrode, and the bottom electrode may be a cathode or an anode. Specifically, when the bottom electrode is an anode, the top electrode is a cathode; when the bottom electrode is a cathode, the top electrode is an anode. In some embodiments, the anode may use ITO, but it is not limited thereto. In some embodiments, the cathode may use metal electrodes, including but not limited to silver electrodes and aluminum electrodes. The thickness of the cathode is 60-120nm. In some embodiments of the present application, it is 100nm.

[0046] The method for preparing the quantum dot light-emitting layer on the bottom electrode is not strictly limited, and the quantum dot light-emitting layer may be prepared by a conventional method in the art. In some embodiments, a solution processing method is used on the bottom electrode A quantum dot solution is deposited to prepare a quantum dot light-emitting layer. The quantum dot light-emitting layer prepared by the solution processing method is subjected to ultrasonic treatment in a specific solvent system through the following steps, and the quantum dot impurities and solvent impurities remaining in the quantum dot light-emitting layer, especially the remaining high-boiling solvent, can be further removed Together, it significantly improves the impurity removal effect of the quantum dot light-emitting layer. In some embodiments of the present application, an inkjet printing method is used to deposit quantum dot ink on the bottom electrode to prepare a quantum dot light emitting layer. In the embodiments of the present application, the quantum dots in the quantum dot light-emitting layer are conventional quantum dots in the art. In some embodiments, the thickness of the quantum dot light-emitting layer is 30-50 nm

[0047] In the above step S20, the quantum dot light emitting layer is immersed in a solvent system for ultrasonic treatment, and by ultrasonic treatment, a small amount of doping solvent present in the solvent system penetrates into the quantum dot light emitting layer to dissolve the quantum dot Impurities in the light-emitting layer (impurities introduced by quantum dots and/or impurities formed by residual solvents), thereby removing the influence of residual impurities on the luminous efficiency and service life of quantum dot light-emitting diodes, and ultimately improving the luminous efficiency and use of quantum dot light-emitting diodes life.

[0048] In the embodiment of the present application, the quantum dot light emitting layer is immersed in a solvent system to perform ultrasonic treatment, and the quantum dot light emitting layer is subjected to ultrasonic treatment to remove impurities. For ease of operation, in some embodiments, the entire substrate prepared with the quantum dot light-emitting layer is placed in a solvent system for ultrasonic treatment.

[0049] In the embodiments of the present application, the solvent system includes a host solvent and a doping solvent dissolved in the host solvent to form a uniform solvent system. The polarity of the doping solvent is less than the polarity of the host solvent, and the host solvent is an organic solvent that does not dissolve quantum dots. The solvent system thus formed can effectively remove residual impurities in the quantum dot light-emitting layer. The host solvent does not dissolve the light-emitting layer, the doping solvent can dissolve the quantum dot light-emitting layer, and the low concentration of the dopant solvent in the host solvent can dissolve impurities of relatively low molecular weight without destroying the nanoparticles of the light-emitting layer.

[0050] In some embodiments, the host solvent is selected from alcohols with less than 20 carbon atoms in the linear chain, esters with less than 20 carbon atoms in the linear chain, and fewer than 20 carbon atoms in the linear chain One or a combination of two or more ketones and alcohol derivatives with a linear number of carbon atoms less than 10.

[0051] In some embodiments, the alcohols in the linear chain having less than 20 carbon atoms are selected from 1-propanol and 1-butanol

, 1-pentanol, 2-pentanol, 1,5-pentanediol and 2,3-butanediol. In some embodiments, the esters with less than 20 carbon atoms in the linear chain are selected from ethyl acetate, ethyl propionate, ethyl methacrylate, and ethyl benzoate. In some embodiments, the ketones having less than 20 carbon atoms in the linear chain It is selected from acetone, methyl ethyl ketone, 3-pentanone, 2-methyl 4-octanone. In some embodiments, the alcohol derivative having a carbon number of less than 10 in the linear chain is selected from the group consisting of methoxyethanol, ethoxyethanol, ethyl 2-hydroxy-2-phenylacetate and acetone alcohol One or more. In some embodiments, the doping solvent is selected from unsaturated fatty acids with less than 10 carbon atoms in the straight chain, alcohol derivatives with less than 10 carbon atoms in the straight chain, and less than 10 carbon atoms in the straight chain One or a combination of two or more of saturated acids of 10, acid derivatives with less than 15 carbon atoms in the linear chain, and halogenated hydrocarbons with less than 20 carbon atoms in the linear chain.

[0052] In the examples of the present application, the polarity of the solute is less than or equal to the polarity of the host solvent, and may even have a certain solubility in quantum dots, but after mixing with the host solvent to form a solution, due to the amount of added Low, will not cause the dissolution of quantum dots.

[0053] In some embodiments, the unsaturated fatty acid having a carbon number of less than 10 is selected from acrylic acid, crotonic acid, methacrylic acid, and 3-pentenoic acid. In some embodiments, the alcohol derivative having a carbon number of less than 10 in the linear chain is selected from methoxyethanol, ethoxyethanol, phenoxyethanol, and 1-methoxy-1,2-propanediol One or more of them. In some embodiments, the saturated acids with less than 10 carbon atoms in the linear chain are selected from one or more of acetic acid, propionic acid, butyric acid, and valeric acid. In some embodiments, the acid derivative having less than 15 carbon atoms in the linear chain is selected from one of perfluorooctanoic acid, perfluorodecylphosphonic acid, perchlorodecylcarboxylic acid, and perfluorododecanoic acid Or more. In some embodiments, the halogenated hydrocarbon with a carbon number of less than 20 in the linear chain is selected from one or more of fluoropropane, 1-chlorobutane, 1-chlorohexane, and 3-fluorohexane

[0054] On the basis of the above embodiment, based on the total weight of the solvent system is 100%, the weight percentage of the doping solvent is 0-0.5%, but not 0. If the content of the low-polarity doping solvent in the solvent system is too high, part of the quantum dots in the quantum dot light-emitting layer may be dissolved, thereby affecting the function of the quantum dot light-emitting layer. In some embodiments of the present application, the weight percentage of the doping solvent is 0.001-0.05%

[0055] In some embodiments, in the step of immersing the quantum dot light emitting layer in a solvent system for ultrasonic treatment, the frequency of the ultrasonic treatment is 20 kHz-10 ⁹ kHz. If the frequency of the ultrasonic treatment is too high, it will affect the stability of the formed film layer including the quantum dot light-emitting layer, and the film layer is easily detached from the substrate, thereby destroying the stability of the device structure. If the frequency of the ultrasonic treatment is too low, the effect of removing impurities in the quantum dot light-emitting layer is not obvious, and the effect of improving the service life and luminous efficiency of the quantum dot light-emitting diode is not significant . In some embodiments of the present application, in the step of immersing the quantum dot light emitting layer in a solvent system for ultrasonic treatment, the frequency of the ultrasonic treatment is 20 kHz-100 kHz

[0056] In some embodiments, in the step of immersing the quantum dot light-emitting layer in a solvent system for ultrasonic treatment, the power density of the ultrasonic treatment is 0.3-200 w/cm ² if the power density of the ultrasonic treatment is excessive High, it will affect the stability of the formed film layer including the quantum dot light-emitting layer, the film layer is easily detached from the substrate, thereby destroying the stability of the device structure. If the power density of the ultrasonic treatment is too low, the effect of removing impurities in the quantum dot light-emitting layer is not obvious, and the effect of improving the service life and luminous efficiency of the quantum dot light-emitting diode is not significant. In some embodiments of the present application, in the step of immersing the quantum dot light-emitting layer in a solvent system to perform ultrasonic treatment, the power density of the ultrasonic treatment is 5-100 w/cm

[0057] In some embodiments, the step of immersing the quantum dot light emitting layer in a solvent system for ultrasonic treatment, the ultrasonic treatment time is 20 minutes-48 hours. If the ultrasonic treatment time is too long, the ultrasonic treatment for a long time will affect the stability of the formed film layer including the quantum dot light-emitting layer, and the film layer is easily detached from the substrate, thereby destroying the stability of the device structure. If the time of the ultrasonic treatment is too short, a better effect of removing impurities in the quantum dot light-emitting layer cannot be achieved. In some embodiments of the present application, in the step of immersing the quantum dot light emitting layer in a solvent system to perform ultrasonic treatment, the ultrasonic treatment time is 1 hour to 10 hours.

[0058] In the above step S20, the top electrode is prepared on the surface of the quantum dot light-emitting layer after ultrasonic treatment away from the bottom electrode, which can be prepared by a conventional method in the art. It is worth noting that the top electrode in the embodiment of the present application is an electrode opposite to the top electrode, and may specifically be an anode or a cathode.

[0059] Thus, a quantum dot light-emitting diode having a basic structure (including a cathode and an anode disposed oppositely, and a quantum dot light-emitting layer disposed between the cathode and the anode) is prepared in the embodiments of the present application. In order to obtain better device performance, different functional layers can be introduced on the basic structure of the quantum dot light-emitting diode to balance carriers.

[0060] In some embodiments, when the bottom electrode is an anode, that is, the anode is provided on the substrate to form an anode substrate, before preparing the quantum dot light emitting layer, it further includes preparing a hole function layer on the anode surface of the substrate ( The step of providing the hole functional layer between the anode and the quantum dot light-emitting layer). The hole functional layer includes at least one of a hole injection layer, a hole transport layer, and an electron blocking layer. Wherein, the hole injection layer and the hole transport layer are used to reduce the difficulty of hole injection, and the electron blocking layer is used to block excess Electrons, so that excessive electrons cannot reach the anode to form a leakage current, thereby improving the current efficiency of the quantum dot light-emitting diode. In some embodiments of the present application, when the anode is provided on the substrate to form the anode substrate, before preparing the quantum dot light emitting layer, the method further includes: preparing a hole injection layer on the anode surface of the substrate, and injecting the hole The step of preparing a hole transport layer on the side of the layer facing away from the anode. Wherein, the material of the hole injection layer may be a conventional hole injection material, including but not limited to PEDOT:PSS. The material of the hole transport layer may be employed conventional hole transporting materials, including but not limited to NPB, TFB and other organic materials, and _N iO, _Mo0 ₃ inorganic composite materials and the thickness of the hole transport layer 10-100nm.

[0061] In some embodiments, when the bottom electrode is an anode, that is, the anode is provided on the substrate to form an anode substrate, after preparing the quantum dot light-emitting layer, and before preparing the cathode, further including diverging from the quantum dot light-emitting layer The step of preparing an electronic functional layer on one side of the anode (the electronic functional layer is provided between the cathode and the quantum dot light-emitting layer). The electron functional layer includes at least one of an electron injection layer, an electron transport layer, and a hole blocking layer. Wherein, the electron injection layer and the electron transport layer are used to reduce the difficulty of electron injection, and the hole blocking layer is used to block excess holes, so that the excess holes cannot reach the cathode to form a leakage current, thereby improving the quantum dot light emitting diode Current efficiency. In some embodiments of the present application, when the anode substrate is formed on the substrate to form the anode substrate, after preparing the quantum dot light-emitting layer, and before preparing the cathode, the method further includes: a part of the quantum dot light-emitting layer facing away from the anode An electron transport layer is prepared on the side, and an electron injection layer is prepared on the side of the electron injection layer facing away from the anode. Wherein, the material of the electron injection layer can be a conventional electron hole injection material, including but not limited to LiF and CsF, and the thickness of the electron transport layer is 10-100 nm. The material of the electron transport layer may be a conventional electron transport material, including but not limited to n-type zinc oxide, and the thickness of the electron transport layer is HMOOnm.

[0062] In some embodiments, when the bottom electrode is a cathode, that is, the cathode is provided on the substrate to form a cathode substrate, before preparing the quantum dot light emitting layer, the method further includes the step of preparing an electronic functional layer on the cathode surface of the substrate . The electron functional layer includes at least one of an electron injection layer, an electron transport layer, and a hole blocking layer. In some embodiments of the present application, when the cathode is provided on the substrate to form the cathode substrate, before preparing the quantum dot light emitting layer, the method further includes: preparing an electron injection layer on the cathode surface of the substrate, and the electron injection layer is away from The step of preparing an electron transport layer on one side of the cathode.

[0063] In some embodiments, when the bottom electrode is a cathode, that is, the cathode is provided on the substrate to form a cathode substrate, After preparing the quantum dot light-emitting layer, and before preparing the anode, a step of preparing a hole function layer on the side of the quantum dot light-emitting layer facing away from the cathode is further included. The hole functional layer includes at least one of a hole injection layer, a hole transport layer, and an electron blocking layer. In some embodiments of the present application, when the cathode is provided on the substrate to form the cathode substrate, after preparing the quantum dot light-emitting layer and before preparing the anode, the method further includes: a side of the quantum dot light-emitting layer facing away from the cathode A hole transport layer is prepared, and a hole injection layer is prepared on the side of the hole transport layer facing away from the cathode.

[0064] For the preparation of the aforementioned electronic functional layer and hole functional layer, refer to the conventional methods in the art. In some examples of the present application, the solution processing method is used for preparation.

[0065] The following is a description with reference to specific embodiments.

Example 1

[0067] A method for manufacturing a quantum dot light emitting diode includes the following steps:

[0068] A substrate provided with an anode (ITO) is provided, a hole injection layer (PEDOT:PSS) is prepared on the anode, and a hole transport layer (TFB) is prepared on the hole transport layer on the side of the hole injection layer facing away from the anode The quantum dot light-emitting layer (CdSe/ZnS QDs) is prepared on the side facing away from the anode;

[0069] The quantum dot light-emitting layer is immersed in a 1-chlorobutane content of 1-ppm 1-butanol solution, ultrasonic treatment at 20kHz power lOOmin;

[0070] Preparation of an electron transport layer (ZnO) on the surface of the quantum dot luminescent layer after ultrasonic treatment away from the anode Preparation of an electron injection layer (LiF) on the surface of the electron transport layer away from the anode Electron injection layer away from the anode Aluminum cathode was prepared on the surface.

Example 2

[0072] A method for preparing a quantum dot light emitting diode, the difference from Example 1 is that: the quantum dot light emitting layer is immersed in 1-chlorobutane content is 100

In 1-ppm butanol solution, sonicated at 20kHz for 100min.

Comparative Example 1

[0074] A method for preparing a quantum dot light emitting diode, the difference from Example 1 is that: the quantum dot light emitting layer is immersed in 1-chlorobutane content is 100

In 1-butanol solution of ppm, sonicated at 20kHz for 300min.

Comparative Example 2 [0076] A method for preparing a quantum dot light-emitting diode is different from that in Example 1 in that: the quantum dot light-emitting layer is immersed in 1-butanol, and ultrasonically processed at a power of 20 kHz for 100 min.

Comparative Example 3

[0078] A method for preparing a quantum dot light-emitting diode is different from Example 1 in that: an electron transport layer (ZnO) is directly prepared on the surface of the prepared quantum dot light-emitting layer, and the electron transport layer faces away from the anode An electron injection layer (LiF) is prepared on the surface, and an aluminum cathode is prepared on the surface of the electron injection layer facing away from the anode. That is, without "dipping the quantum dot light-emitting layer into 1-chlorobutane content of 1

In a 1-ppm alcohol solution of ppm, sonicate at a power of 20kHz for 100min steps.

[0079] The external quantum efficiency changes (%) of the quantum dot light-emitting diodes prepared in Examples 1-2 and Comparative Examples 1-3 after energization and aging were tested, and the results are shown in Table i below.

Table 1

[]

[] [Table 1]

[0081] It can be seen from Table 1 above that when the mass ratio of 1-butanol solution of 1-chlorobutane is within a certain range, the external quantum efficiency of the device after ultrasonic treatment can effectively improve the external quantum efficiency of the quantum dot light emitting diode. In particular, when the mass ratio of 1-chlorobutane in 1-butanol is 100 ppm, the maximum value of the external quantum efficiency of the quantum dot light-emitting diode is increased by 37.3%.

Example 3

[0083] A method for preparing a quantum dot light emitting diode includes the following steps: [0084] A substrate provided with an anode (ITO) is provided, a hole injection layer (PEDOT:PSS) is prepared on the anode, a hole transport layer (TFB) is prepared on the side of the hole injection layer facing away from the anode, and the hole The quantum dot light-emitting layer (CdSe/ZnS QDs) is prepared on the side of the transport layer facing away from the anode;

[0085] The quantum dot light-emitting layer is immersed in the solvent system of Example 2 in Table 2 below, ultrasonic treatment at 20kHz power lOOmin;

[0086] An electron transport layer (ZnO) is prepared on the surface of the quantum dot light-emitting layer after ultrasonic treatment facing away from the anode

An electron injection layer (LiF) is prepared on the surface of the electron transport layer facing away from the anode, and an aluminum cathode is prepared on the surface of the electron injection layer facing away from the anode.

Example 4

[0088] A method for preparing a quantum dot light-emitting diode is different from Example 3 in that: the quantum dot light-emitting layer is immersed in the solvent system of Example 4 in Table 2 below, and is sonicated for 100 min at a power of 20 kHz.

Example 5

[0090] A method for preparing a quantum dot light-emitting diode, which is different from Example 3 in that: the quantum dot light-emitting layer is immersed in the solvent system of Example 5 in Table 2 below, and is sonicated at a power of 20 kHz for 100 min.

Example 6

[0092] A method for preparing a quantum dot light-emitting diode is different from Example 3 in that: the quantum dot light-emitting layer is immersed in the solvent system of Example 6 in Table 2 below, and is sonicated for 100 min at a power of 20 kHz.

[0093] The external quantum efficiency changes (%) of the quantum dot light-emitting diodes prepared in Examples 4-6 and Comparative Example 3 after energization and aging were tested, and the results are shown in Table 2 below.

Table 2

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[Table 2]

[0095] It can be seen from Table 2 that different combinations of solvent systems have different degrees of influence on the external quantum efficiency of quantum dot light-emitting diodes. Specifically, Example 3 and Example 5 significantly improve the external quantum efficiency of quantum dot light-emitting diodes Example 4 improves the external quantum efficiency of the quantum dot light emitting diode, and at the same time improves the ripening time of the quantum dot light emitting diode to reach the highest external quantum efficiency.

[0096] The above are only optional embodiments of the present application, and are not intended to limit the present application. For those skilled in the art, this application may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of this application shall be included in the scope of the claims of this application.

Claims

[Claim 1] The preparation method of quantum dot light-emitting diode, characterized in that it comprises the following steps:

Providing a substrate, a quantum dot light emitting layer is provided on the upper surface of the substrate; immersing the substrate in a solvent system for ultrasonic treatment, the solvent system includes a host solvent and a doping solvent dissolved in the host solvent, the doping The polarity of the hetero solvent is less than the polarity of the host solvent, and the host solvent is an organic solvent that does not dissolve quantum dots.

[Claim 2] The method for preparing a quantum dot light-emitting diode according to claim 1, wherein the host solvent is selected from alcohols having a number of carbon atoms in the linear chain of less than 20, and the number of carbon atoms in the linear chain One or a combination of two or more of esters less than 20 and ketones with less than 20 carbon atoms in the linear chain.

[Claim 3] The method for preparing a quantum dot light-emitting diode according to claim 2, wherein the alcohols with a carbon number of less than 20 in the linear chain are selected from 1-propanol, 1-butanol, One or more of 1-pentanol, 2-pentanol, 1,5-pentanediol, and 2,3-butanediol.

[Claim 4] The method for preparing a quantum dot light-emitting diode according to claim 2, wherein the esters with less than 20 carbon atoms in the linear chain are selected from ethyl acetate, ethyl propionate, and methyl acetate Ethyl acrylate, ethyl benzoate.

[Claim 5] The method for manufacturing a quantum dot light-emitting diode according to claim 2, wherein the ketones with the number of carbon atoms in the linear chain less than 20 are selected from acetone, methyl ethyl ketone, 3-pentanone, 2-methyl 4-octanone.

[Claim 6] The method for preparing a quantum dot light-emitting diode according to claim 2, wherein the alcohol derivative having a carbon number of less than 10 in the linear chain is selected from methoxyethanol and ethoxy One or more of ethanol and ethyl mandelic acid.

[Claim 7] The method for manufacturing a quantum dot light emitting diode according to claim 1, wherein the doping solvent is selected from unsaturated fatty acids with less than 10 carbon atoms in the linear chain and carbon in the linear chain Alcohol derivatives with less than 10 atoms, saturated acids with less than 10 carbon atoms in straight chain, acid derivatives with less than 15 carbon atoms in straight chain, and halogens with less than 20 carbon atoms in straight chain One or a combination of two or more of the substituted hydrocarbons.

[Claim 8] The method for manufacturing a quantum dot light-emitting diode according to claim 7, characterized in that The unsaturated fatty acid having less than 10 carbon atoms is selected from one or more of acrylic acid, crotonic acid, methacrylic acid, and 3-pentenoic acid.

[Claim 9] The method for preparing a quantum dot light-emitting diode according to claim 7, wherein the alcohol derivative having a carbon number of less than 10 in the linear chain is selected from methoxyethanol and ethoxy One or more of ethanol, ethyl 2-hydroxy-2-phenylacetate, and acetol.

[Claim 10] The method for preparing a quantum dot light-emitting diode according to claim 7, wherein the saturated acids with the number of carbon atoms in the linear chain less than 10 are selected from acetic acid, propionic acid, butyric acid and amyl One or more of acids.

[Claim 11] The method for preparing a quantum dot light-emitting diode according to claim 7, wherein the acid derivative with a carbon number of less than 15 in the linear chain is selected from perfluorooctanoic acid and perfluorodecylphosphonic acid , One or more of perchlorodecyl carboxylic acid and perfluorododecanoic acid.

[Claim 12] The method for preparing a quantum dot light-emitting diode according to claim 7, characterized in that the halogenated hydrocarbons with a carbon number of less than 20 in the linear chain are selected from fluoropropane, 1-chlorobutane, One or more of 1-chlorohexane and 3-fluorohexane.

[Claim 13] The method for preparing a quantum dot light emitting diode according to any one of claims 1 to 12, characterized in that, based on the total weight of the solvent system being 100%, the weight of the doping solvent is 100 The content is 0.001-0.5%.

[Claim 14] The method for manufacturing a quantum dot light emitting diode according to any one of claims 1 to 12, characterized in that, in the step of immersing the substrate in a solvent system for ultrasonic treatment, the frequency of the ultrasonic treatment From 20 kHz to 10 ⁹ kHz.

[Claim 15] The method for manufacturing a quantum dot light-emitting diode according to claim 14, characterized in that in the step of immersing the substrate in a solvent system for ultrasonic treatment, the frequency of the ultrasonic treatment is 20 kHz-100 kHz .

[Claim 16] The method for manufacturing a quantum dot light emitting diode according to any one of claims 1 to 12, characterized in that in the step of immersing the quantum dot light emitting layer in a solvent system for ultrasonic treatment, the ultrasonic The processing power density is 0.3-200 w/cm ² .

[Claim 17] The method for manufacturing a quantum dot light-emitting diode according to claim 16, characterized in that in the step of immersing the quantum dot light-emitting layer in a solvent system for ultrasonic treatment, the super The power density of sonication is 5-100w/cm ² .

[Claim 18] The method for manufacturing a quantum dot light emitting diode according to any one of claims 1 to 12, characterized in that in the step of immersing the quantum dot light emitting layer in a solvent system for ultrasonic treatment, the ultrasonic The treatment time is from 20 minutes to 48 hours.

[Claim 19] The method for manufacturing a quantum dot light emitting diode according to claim 18, characterized in that, in the step of immersing the quantum dot light emitting layer in a solvent system for ultrasonic treatment, the ultrasonic treatment time is 1 Hour-10 hours.

[Claim 20] The method of manufacturing a quantum dot light emitting diode according to any one of claims 1 to 12, wherein the substrate is a substrate provided with a bottom electrode.

[Claim 21] The method for manufacturing a quantum dot light-emitting diode according to claim 20, wherein the bottom electrode is an anode, and before preparing the quantum dot light-emitting layer, further comprising preparing an empty surface on the anode surface of the substrate Step of the hole functional layer; the hole functional layer includes at least one of a hole injection layer, a hole transport layer, and an electron blocking layer.

[Claim 22] The method for manufacturing a quantum dot light-emitting diode according to claim 20, wherein the bottom electrode is an anode, and before preparing the cathode, the method further includes that the quantum dot light-emitting layer faces away from the anode A step of preparing an electronic functional layer on one side; the electronic functional layer includes at least one of an electron injection layer, an electron transport layer, and a hole blocking layer.